An automaton A can be represented by a graph whose
nodes and arcs represent the states and the transitions of
A, respectively. An arc from q to r labeled by the event σ
represents the transition q →σ r. Several arcs labeled σ1 , · · · , σn
linking the same pair of states q, r can be represented by a single arc labeled by the set { σ1, · · · , σn}. In this paper, the
initial state q 0 is indicated by a small incoming arrow and final
states are the rightmost states in the graph of the automaton.